High frequency of an otherwise rare phenotype in a small and isolated tiger population
Vinay Sagar, Christopher B. Kaelin, Meghana Natesh, P. Anuradha Reddy, Rajesh Kumar Mohapatra, Himanshu Chhattani, Prachi Thatte, Srinivas Vaidyanathan, Suvankar Biswas, Supriya Bhatt, Shashi Bala Paul, Yadvendradev V. Jhala, Mayank Verma, Bivash Pandav, Samrat Mondol, Gregory S. Barsh, Debabrata Swain, Uma Ramakrishnan
Abstract
Significance Small and isolated populations have low genetic variation due to founding bottlenecks and genetic drift. Few empirical studies demonstrate visible phenotypic change associated with drift using genetic data in endangered species. We used genomic analyses of a captive tiger pedigree to identify the genetic basis for a rare trait, pseudomelanism, in tigers. Genome sequencing and extensive genotyping of noninvasive samples across tiger range revealed unique spatial presence of this allele in the Similipal Tiger Reserve, India. Population genetic analyses confirmed that Similipal is a small and isolated population. Simulations suggest that intense founding bottlenecks could result in the observed patterns, implicating drift. Our study highlights ongoing phenotypic evolution, potentially from human-induced fragmentation, in endangered large carnivore populations.